Method and apparatus for altering biomechanics of articular joints

Abstract

Pathology of the human knee can arise from excessive and/or uneven loading of regions within the joint. Methods and apparatus are disclosed that enable displacement of soft tissue around the knee, without displacing or severing bone thereby altering the mechanical load distribution within the joint in a less invasive manner than previous techniques.

The invention claimed is: 
     
       1. An apparatus for treating disorders of articular joints, the joint being subject to forces exerted by soft tissues disposed proximate to the joint with said soft tissues forming target tissues for treatment, the apparatus comprising a prosthesis implantable in engagement with at least one said target tissue so as to displace said target tissue sufficiently to alter the location, angle or magnitude of the forces exerted by the soft tissues so as to achieve a therapeutic effect in the joint, wherein said prosthesis comprises:
 a fixation portion including bone fixation means configured to be secured in contact with a bone forming said joint at a fixation location outside the articular capsule of the joint, and 
 a displacement portion configured and dimensioned to extend from the fixation portion to engage and displace the soft tissue, the displacement portion having an outer surface, wherein said displacement portion outer surface is smooth and free of holes or fixation means; 
 wherein the fixation portion of the prosthesis is configured to be mounted to the humerus. 
 
     
     
       2. The apparatus of  claim 1 , wherein the displacement portion is further configured and dimensioned to extend between the target tissue and a bone, and to atraumatically engage and displace the target tissue outwardly, away from said bone. 
     
     
       3. The apparatus of  claim 2 , wherein said bone is a bone to which the target tissue is attached. 
     
     
       4. The apparatus of  claim 2 , wherein:
 the displacement portion has an inner, bone facing surface; and 
 the displacement portion is further configured and dimensioned to position at least a portion of said inner, bone facing surface spaced from the bone. 
 
     
     
       5. The apparatus of  claim 4 , wherein a portion of said inner, bone facing surface of the displacement portion is further configured in part to rest against said bone to further support the displacement portion. 
     
     
       6. The apparatus of  claim 2 , further comprising a spanning section providing a transition between the displacement portion and fixation portion, wherein the fixation portion has an inner, bone engaging surface shaped to conform to the bone at said fixation location. 
     
     
       7. The apparatus of  claim 6 , wherein said prosthesis is configured to position the displacement portion to displace the target tissue outwardly from a natural path by distance of about 5 mm to about 30 mm. 
     
     
       8. A apparatus for treating disorders of articular joints, the joint being subject to forces exerted by soft tissues disposed proximate to the joint with said soft tissues forming target tissues for treatment, the apparatus comprising a prosthesis implantable in engagement with at least one said target tissue so as to displace said target tissue sufficiently to alter the location, angle or magnitude of the forces exerted by the soft tissues so as to achieve a therapeutic effect in the joint, wherein said prosthesis comprises:
 a fixation portion including bone fixation means configured to be secured in contact with a bone forming said joint at a fixation location outside the articular capsule of the joint, 
 a displacement portion configured and dimensioned to extend from the fixation portion to engage and displace the soft tissue, the displacement portion having an outer surface, wherein said displacement portion outer surface is smooth and free of holes or fixation means; and 
 a spanning section providing a transition between the displacement portion and fixation portion, wherein the fixation portion has an inner, bone engaging surface shaped to conform to the bone at said fixation location, 
 wherein the displacement portion is further configured and dimensioned to extend between the target tissue and a bond, and to atraumatically engage and displace the target tissue outwardly, away from said bone; and 
 wherein the fixation portion is further configured and dimensioned to lie substantially in a different anatomical plane than the displacement portion when secured at the fixation location. 
 
     
     
       9. An apparatus for treating disorders of articular joints, the joint being subject to forces exerted by soft tissues disposed proximate to the joint with said soft tissues forming target tissues for treatment, the apparatus comprising a prosthesis implantable in engagement with at least one said target tissue so as to displace said target tissue sufficiently to alter the location, angle or magnitude of the forces exerted by the soft tissues so as to achieve a therapeutic effect in the joint, wherein said prosthesis comprises:
 a fixation portion including bone fixation means configured to be secured in contact with a bone forming said joint at a fixation location outside the articular capsule of the joint, 
 a displacement portion configured and dimensioned to extend from the fixation portion to engage and displace the soft tissue, the displacement portion having an outer surface, wherein said displacement portion outer surface is smooth and free of holes or fixation means, and 
 a spanning section providing a transition between the displacement portion and fixation portion, wherein the fixation portion has an inner, bone engaging surface shaped to conform to the bone at said fixation location; 
 wherein the displacement portion is further configured and dimensioned to extend between the target tissue and a bone, and to atraumatically engage and displace the target tissue outwardly, away from said bone; and 
 wherein the displacement portion lies substantially in an inclined plane, said plane being inclined outwardly with respect to the fixation portion. 
 
     
     
       10. The apparatus of  claim 9 , wherein:
 the displacement portion has a substantially round profile lying in said inclined plane; and 
 the displacement portion outer surface is substantially convex in an outward direction with respect to said inclined plane. 
 
     
     
       11. An apparatus for treating disorder of articular joints, the joint being subject to forces exerted by soft tissues disposed proximate to the joint with said soft tissues forming target tissues for treatment, the apparatus comprising a prosthesis implantable in engagement with at least one said target tissue so as to displace said target tissue sufficiently to alter the location, angle or magnitude of the forces exerted by the soft tissues so as to achieve a therapeutic effect in the joint, wherein said prosthesis comprises:
 a fixation portion including bone fixation means configured to be secured in contact with a bone forming said joint at a fixation location outside the articular capsule of the joint, and 
 a displacement portion configured and dimensioned to extend from the fixation portion to engage and displace the soft tissue, the displacement portion having an outer surface, wherein said displacement portion outer surface is smooth and free of holes or fixation means, 
 
       wherein:
 the prosthesis is formed around a first axis lying in a first plane; 
 the fixation portion lies substantially in said first plane with a generally elongate shape oriented along said first axis and has first and second ends and at least a first width; 
 the displacement portion outer surface is a convex surface spaced from the second end of said fixation portion in a direction along said first axis and in a direction perpendicular to said first plane; 
 the displacement portion has an inner concave inner surface facing said first plane, the displacement portion having a second width greater than the first width of said fixation portion; and 
 a spanning section extending between the second end of said fixation portion and the displacement portion. 
 
     
     
       12. The apparatus of  claim 11 , wherein:
 the prosthesis has an overall length along said first axis of between about 85-115 mm; 
 the fixation portion has a length of between about 40-50 mm and a first width of between about 12 mm and about 15 mm; 
 the displacement portion has a length of about 45-60 mm and a second width of about 45-60 mm; and 
 an outermost point on the convex bearing surface is displaced from the first plane by a distance of about 10-45 mm. 
 
     
     
       13. An apparatus for treating disorders of articular joints, the joint being subject to forces exerted by soft tissues disposed proximate to the joint with said soft tissues forming target tissues for treatment, the apparatus comprising a prosthesis implantable in engagement with at least one said target tissue so as to displace said target tissue sufficiently to alter the location, angle or magnitude of the forces exerted by the soft tissues so as to achieve a therapeutic effect in the joint, wherein said prosthesis comprises:
 a fixation portion including bone fixation means configured to be secured in contact with a bone forming said joint at a fixation location outside the articular capsule of the joint, and 
 a displacement portion configured and dimensioned to extend from the fixation portion to engage and displace the soft tissue, the displacement portion having an outer surface, wherein said displacement portion outer surface is smooth and free of holes or fixation means; 
 
       wherein:
 the fixation portion is formed around a first axis lying substantially in said first plane with a generally elongate shape oriented along said first axis and having first and second ends and at least a first width; 
 the displacement portion having an outer, convex bearing surface and an inner concave surface, said surfaces spaced from the second end of said fixation portion in a direction along said axis and in a direction perpendicular to the first axis, the convex bearing surface further having a generally arcuate shape formed around a second axis parallel to and spaced from the first axis, the displacement portion having a width substantially the same as the first width; and 
 a spanning section extending between the second end of said fixation portion and the displacement portion. 
 
     
     
       14. The apparatus of  claim 13 , wherein:
 the fixation portion and displacement portions have widths ranging from about 10 mm to about 25 mm; 
 the fixation portion has a length ranging from about 20 mm to about 50 mm; 
 the displacement portion has a length ranging from about 20 mm to about 50 mm; and 
 an outermost point on the convex bearing surface is displaced from the first axis by a distance of about 10-45 mm. 
 
     
     
       15. The apparatus of  claim 13 , wherein the displacement portion is positioned at an angle with respect to the fixation portion of between about 80 degrees and about 135 degrees. 
     
     
       16. A method of treating a shoulder joint having first and second bones, the method comprising:
 fixing a fixation portion of a treatment device to the first bone such that a displacement portion of the treatment device engages target tissue in a pretreatment location proximate the shoulder joint; and 
 displacing the target tissue from the pretreatment location with the displacement portion of the treatment device by a distance and in a direction selected to provide a therapeutic effect in the shoulder joint. 
 
     
     
       17. The method of  claim 16 , wherein the therapeutic effect comprises reducing pain in the shoulder joint. 
     
     
       18. The method of  claim 16 , wherein the therapeutic effect comprises increasing stability of the shoulder joint. 
     
     
       19. The method of  claim 16 , wherein the first bone is the humerus.